Cylinder lock

ABSTRACT

A key operable plug mechanism having a body, a side bar movable to engage the body, a plurality of tumblers, a cylinder for said tumblers, each of said tumblers having a key engaging surface and a side bar accommodating notch the arrangement being such that on insertion of an appropriate key and rotation of the same, the key engaging surfaces are picked-up to align the notches of the tumblers and such that the rotary motion of the key is transmitted to said side bar through said cylinder.

United States Patent 1. Taylor [4 11 Mar. 19, 1974 CYLINDER LOCK [75]Inventor: Jack William Taylor, Bournemouth,

England [73] Assignee: Ingersoll Locks Limited, Ascot,

Berkshire, England [22] Filed: July 21, 1972 [21] Appl. No.: 273,863

[30] Foreign Application Priority Data July 28, 1971 Great Britain35430/71 [52] U.S. Cl. 70/366, 70/377 [51] Int. CL, E051) 29/00 [58]Field of Search 70/366, 365, 362, 377

[56] References Cited UNITED STATES PATENTS 3,681,956 8/1972 Niilola70/366 1,545,046 7/1925 Epstein 70/366 X FOREIGN PATENTS OR APPLICATIONS5/1968 Canada 70/366 Primary Examiner-Robert L. Wolfe Attorney, Agent,or Firm-Edwin E. Greigg 5 7] ABSTRACT A key operable plug mechanismhaving a body, a side bar movable to engage the body, a plurality oftumblers, a cylinder for said tumblers, each of said tumblers having akey engaging surface and a side bar accommodating notch the arrangementbeing such that on insertion of an appropriate key and rotation of thesame, the key engaging surfaces are picked-up to align the notches ofthe tumblers and :such that the rotary motion of the key is transmittedto said side bar through said cylinder.

11 Claims, 24 Drawing Figures PATENTEDHARIQIHM r 3797.290

SHEEIEUFG 5! F lG.5b. F /G.5c.

PATENTEUHARIS I974 3797290 v SHEET 5 0F 6 125 124 123 FIG. 74a.

' FIG. 74b.

CYLINDER LOCK The present invention relates to a lock and withparticular reference to a plug or similar mechanism suitable forinclusion in a revolving barrel-type lock mechanism intended forassociation with or forming part of a lock.

The present invention provides a key operable plug mechanism having abody a side bar movable to engage the body, a plurality of tumblers, acylinder for said elements, each tumbler having a key engaging surfaceand a side bar accomodating notch the arrangement being such that oninsertion of an appropriate key and rotation of the same, the keyengaging surfaces are pickedup to align the notches of the tumblers andsuch that the rotary motion of the key is transmitted to said side barthrough said cylinder.

According to the present invention, there is provided a key operableassembly for a lock which comprises a body member having a generallycylindrical bore, a rotatable plug disposed within said bore, side barmeans movable between a locking position in which said side bar meansengages said body member to prevent substantial relative rotationbetween said plug and said body member and a free position in which saidside bar means is disengaged from said body member to permit saidrelative rotation therebetween, a plurality of tumblers disposed withinsaid plug and each capable of rotation about the plug axis, each tumblerhaving a key engaging surface and a peripheral notch, the said notchbeing adapted to accomodate at least part of said'side of the side barwhen the side bar is disposed in the locking position. The recess mayhave a chamfe'red longitudinal cam surface whereby on rotation of thekey, the rotation is imparted to said side bar by means of the cylinderto urge an extremity of the side bar against the cam surface to causethe side bar to react against the surface and to enter the alignednotches of the plug to permit continued rotation of the plug relative tothe body member. In one embodiment of the present in vention the sidebar may be arranged for rotation with the cylinder so that rotation of akey from a datum position causes rotation of the plug until theextremity of the side bar abuts said cam surface, the rotation of thebar means and-being disposed in fixed angular relationship with said keyengaging surface whereby when the side bar means is in the lockingposition the peripheral notches of said tumblers are dispersed so thatthe periphery of at least one of said elements prevents movement of theside bar means out of engagement with said member, and a cylinder forsaid tumblers, the arrangement being such that on insertion and rotationof an appropriate key, the tumblers will be engaged by said key onrotation thereof to produce relative rotation between said tumblers orsets of tumblers to align said notches to allow movement of said sidebar means, the rotary motion of said key bieng transmitted to saidcylinder to rotate said plug with respect to said body member.

With the tumblers dispersed in the locked position, that is to say, withthe notches and the tumblers misaligned, the key engaging surfaces mayalso be dispersed so that on rotation of the key, lost motion betweensome of said tumblers is taken up until all of the key engaging surfacesare abutting the key whereupon the notches are aligned.

The cylinder may comprise a front plate, a back plate and a bridge pieceto maintain said front plate and said back plate in spaced parallelrelationship. The side bar may be a longitudinal member slidableradially of the plug out of and into the aligned notches of thetumblers. Alternatively, the side bar may be a pivotable member having aprojection longitudinal of the plug and adjacent thereto whereby saidprojection may enter into the aligned notches and the side bar may moveout of engagement with an associated cooperating portion of the bodymember.

The co-operating portion of the body-member may comprise a longitudinalrecess in a surface adjacent the plug which recess is adapted toaccomodate a portion key permitting the take up of the lost motionprovided between some at least of the tumblers, thereby permittingalignment of the notches at the periphery thereof. Continued rotation ofthe key results in presentation of the aligned notch justaposed an innerextremity of said side bar whereby continued rotation of the key causesthe outer extremity of the side bar to coact with said cam surface tourge the side bar inwardly of the plug thereby permitting continuedrotation of the plug relative to the body member.

Alternatively, the side bar may be disposed between a pair of spacedlongitudinal guides located towards the periphery of the plug andparallel to the longitudinal axis thereof. The guides may serve tosupport said side bar for rotation therewith about the axis of the plug.

The guides may be connected to or form part of drive means forconnection to a lock device per se. The cylinder may be arranged forrotation about the plug axis in response to rotationof the key about thesame axis, and may include a bridge piece adapted to abut an adjacentportion of the side bar guide when the notches of the tumblers arealigned to receive the side bar, whereby continued rotation of the keyresults in withdrawal of the side bar into the aligned notches andout ofengagement with said body member.

In another embodiment of the present invention each of the tumblers maybe spring loaded to a datum position so that on removal of a keyappliedturning momerit each detainer will return to its own datum with respectto the cylinder. This is in an additional advantage in the lockconstruction of the present invention since in order to' pick the lock,a lock pick having a number of pick elements corresponding to the numberof tumblers will be required. It will be appreciated, therefore, thatwhere the number of tumblers is of the order of ten the problemsinvolved in picking such a lock are immense.

The following is a description by way of example only with reference tothe accompanying drawings of embodiments of locks in accordance with thepresent invention.

FIG. 1 is a longitudinal section through a barrel lock assembly inaccordance with the present invention;

FIG. 2 is a vertical section along the lines 2 2 of FIG. 1;

FIG. 3 is a front end view of the spring plate assembly at the front endof the lock in FIG. 1;

FIG. 4 is a rear elevation of the lock of FIG. 1;

FIGS. 5a, 5b, 5c and 5d are details of the cylinder of the lock of FIG.1;

FIG. 6 is an end elevation bf a tumbler of the lock of FIG. 1;

FIG. 7 is an end view of a tumbler spacer of FIG. 1;

FIG. 8 is a side view ofa key suitable for use in conjunction with thelock of FIG. 1;

FIG. 9 is a section illustrating an alternative embodiment of thepresent invention;

FIG. 10 is a part section showing an alternative arrangement of thespring plate assembly for a dead lock;

FIG. 11 is a section of a further embodiment of the present invention.

FIG. 12 is a detail of FIG. 11;

FIG. 13 is an end view of the embodiment of FIG. 11;

FIGS. 14a and 14b are details showing the front plate modification ofFIG. 11;

FIG. 15 is a dead lock arrangement for the lock of FIG. 11;

FIG. 16 is a longitudinal section on another embodiment of the presentinvention;

FIG. 17 is a section on line 17 17 of FIG. 16;

FIG. 18 is a detail of the spring plate of FIG. 16;

FIGS. 19a and 19b are details showing a tumbler for use in the assemblyof FIG. 16.

Turning now to FIG. 1, the lock comprises a cylinder body indicatedgenerally at 10 comprising a cylindrical portion 11 terminating at aforward end in a face piece 12. The cylindrical portion 11 of body 10has an internal cylindrical bore 13 which is open at its rearward end 14and terminates at its forward end in an inwardly projecting flange l5.Flange 15 is configured to provide a key aperture 16. The key aperture16 has a central cylindrical opening 17, a forward entrance of which ischamfered at 18, adapted to receive the shank of a key. The aperture 16extends in a radial direction into a rectangular radially disposedbit-accomodating portion 19 (see FIG. '2). The face piece 12 is providedwith a generally planar forward surface at the extremity thereof and isthereafter convexedly curved towards the radial extremity of the facepiece at 20 to terminate in a flange 21 which projects substantiallyradially outwards of cylindrical portion 11. The rearward edge 21 offlange 21 is adapted to abut a surface to which the lock assembly is tobe fitted.

The cylindrical body portion 11 is provided with a pair of diametricallyspaced outwardly extending screw accomodating portions 22 justaposedface piece 12, each of which portions 22 is defined by a longitudinalhemi-cylindrical portion integral with body 11 and accomodating a tappedbore 23' adapted to accomodate connecting screws for securing body 10 toa door or like element housing the locking assembly.

The cylindrical bore 13 is provided towards its rearward end with anannular recess 24 of generally square cross-section.

The cylindrical portion 11 is provided in its external surface with alongitudinally extending enlarged area 25 symmetrically disposed about aradius of cylindrical bore 13 and in angular spaced relationship withthe diameter containing the diametrically disposed screw accomodatingportions 22. The inner surface of cylindrical body portion 1 l definingcylindrical bore 13 is provided adjacent to the enlarged area 25 and acorresponding longitudinally extending side bar recess 26. Recess 26 isdefined by first radial surface 27, an outer surface 28 and a chamferedor cam surface 29, the recess extending in the surface of cylindricalbore 13 rearwardly from face piece 12.

The cylindrical bore 13 of cylindrical portion 11 accomodates a lockcylinder 30 capable of rotation within bore 13 relative to body 10. Thecylinder 30 is retained within said bore 13 by means of an annularcircular clip 31 accomodated within annular recess 24 towards therearward end 14 of cylindrical bore 13, the arrangement being such thatthe cylinder 30 is retained within said bore between forward flange 15and the circular clip 31. The cylinder 30 comprises towards its rearwardend, a plug element 32 including a disc 33 of substantial thickness anda rearwardly extending boss 34. The boss has a diametric slot 35 acrossits rear surface and terminating in the plane containing the rear faceof the disc 33. Disc 33 is counterbored from its forward face tocommunicate with said slot 35. The outer cylindrical surface of boss 34is provided, intermediate disc 32 and its rear surface, with aperipheral recess 37 adapted to accomodate a generally toroidal splitcircular clip 38 having a pair of outwardly extending divergent arms 39whereby the justaposition of the abutting portion of the arms 39 may beprisedapart by means of a screwdriver or like element, the saidjuxtaposition being coincident with an open end of the slot 35. Aconnecting bar 40 having a pair of opposed projections 41 at its forwardend is disposed in diametric slot 35 so that the projections 41 aredisposed forwardly of the circular clip 38 to maintain the connectingbar 40 for rotation with the plug element 32. The arrangement of thecircular clip issuch that by prising apart arms 39, one of projections41 may be hooked over a portion of the retainer disposed across saidslot diametrically opposite said arms 39 and the remaining projection 41may be slipped between the open end of the circular clip 38 forwardly ofthe plane containing the same so that on closure of the arms 39 theprojections 41 of the connecting bar 40 are trapped by said retainer.

The annular front surface 42 of disc 33 is provided at a peripherythereof with a pair of arcuately spaced guide elements 43 extendingforwardly of disc 33. Each guide element is defined by means of an innerarcuate surface 44, an outer arcuate surface 45, a radial surface 46 anda guide surface 47. The guide surfaces 47 of each of guide elements 43are in spaced parallel relationship one with the other. The outerarcuate surface of each guide element 43 is continuous with thecylindrical periphery disc 33 of plug element 32.

Forwardly of plug element 32 there is accomodated within the bore 13 acylinder 48. Cylinder 48 comprises a front end member 49 of generallydisc-shaped configuration, a rear end member 50 also of generallydiscshaped configuration and a bridge element 51 extending between acircumferential part of each said front and said rear end members tomaintain said front end member 49 and rear end member 50 in spacedparallel relationship. The said bridge element is of generally arcuateconfiguration extending through an arc defining an angle ofsubstantially at the axis of bore 13.

The front end member 49 and the rear end member 50 (see FIGS. 50 and c)are each provided with a key accomodating opening 52 corresponding inform to key aperture 16 in face piece 12 and having a central circularaperture part 53 and a radially disposed rectangular aperture part 54communicating therewith, the arrangement being such that the circularand rectangular apertures defining the key opening accomodate the shank108 and bit 109 portions respectively of the key (see FIG. 8) suitablefor insertion therein. The longitudinal axis of rectangular portion 54is contained by the diameter of the disc constituting said front andsaid rear end members which also contains the radial edge of arcuatebridge element 51.

The peripheral edge 55 of front member 49 is cut away in a portionextending substantially 135 if an are from the said diameter, the cutaway portion being defined by first radial abutment surface 56, andinner arcuate surface 57 and a second radial abutment surface 58coincident with said diameter containing the longitudinal axis ofrectangular portion 54, comprising the key opening 52. A notch surface59 is disposed adjacent said second radial abutment surface 58 andspaced inwardly of the arc defining inner arcuate surface 57; a camsurface 60 extends between notch surface 59 and inner arcuate surface 57and extends divergently outwardsof the radius containing the contiguityof cam surface 60 and notch surface 59. The rear end member 50 has aconfiguration which is a mirror image of that of the front end member,and the arrangement is such that the cut-away portion defined by saidsurfaces is adapted to accomodate guide elements 43 of plug element 32for limited relative rotation therebetween, the arcuate extent of thecut-away portion permitting lost motion between said guide elements 43and plug element 32 when rotary drive is applied to carrier 48.

The front face 61 of front cylinder member 49 carries in spaced arcuaterelationship with the rectangular portion 54 of key opening 52 on a sidethereof remote from the said cut-away portion a forwardly projectingsubstantially cylindrical pin 62, the forward portion of which isreduced at 63. The cylinder 48 is arranged to accomodate a plurality, inthis embodiment ten, tumblers 64 each of which is maintained in spacedparallel relation with an adjacent tumbler and/or frontand rear members49 and 50 respectively of carrier 48 by means of spacers 65.

Each tumbler 64 (see FIG. 6) comprises a generally disc-shaped element66 having a first cut-away portion 67 and a second cut-away portion 68in a periphery 69 of disc 66. Each tumbler 64 has a key hole 70comprising a circular portion 71 and a bit accomodating portion 72corresponding to and adapted to co-operate with the rectangular part ofkey opening 52 in front and rear end members 49 and 50 respectively ofthe carrier 48. The bit accomodating part 72 and keyhole 70 is definedby a first surface 73 lying on a chord of the circle containingperipheral edge 69 and a plurality of pickup steps 74 defined by a firstpick-up step 75 which is in spaced parallel relationship with firstsurface 73, a second pick-up step 76 disposed inwardly of first step 75and defining a finite angle with said surface75 to provide an increaseddimension of the keyhole between surface 73 and pick-up surface 76, athird pick-up step 77 disposed inwardly of secondstep 76 and defining anincreased angle with first step 75 and a fourth step 78 which isdisposed at a still further increased angle with respect to first step75 and is disposed at a still further increased angle with respect tofirststep 75 and is disposed inwardly of the surface of third step 77.The arrangement of the pick-up steps 74 is such that insertion of thekey into keyhole 70 provides for the bit to be disposed adjacent pickupsteps 74. The bit is then cut or contoured (see FIG. 8) and adapted toengage with one of said pick-up steps so that on commencing to turn thekey, a bit contoured to engage, say, third pick-up step 77, would takeup a certain amount of lost motion be fore engagement with said step topickup said tumbler whereby different configuration along the bitenables different steps to be picked up on each tumbler therebyproviding a different degree of lost motion between each tumbler onrotation of the key and thereby providing a limited amount of relativerotation between each tumbler on rotation of the key.

The first cut-away portion 67 in a peripheral edge 69 of tumbler 64corresponds with the corresponding cutaway portion of the front and rearend members 49 and 50 respectively of the cylinder 48. The firstcut-away portion is defined by a shoulder 79, an arcuate edge 80 andastep 81, the said step 81 lying on the diameter containing thelongitudinal axis of the generally rectangular portion of keyhole 70.Arcuat'e surface 80 contains an inwardly extending notch 82 of generallysquare cross-section. The notch in each tumbler is in fixed angularrelationship with the pick-up step adapted to be engaged by the key, thearrangement being such that on insertion of the key and rotation thereofthe tumblers will be differentially rotated to align the notches 82 inarcuate edge 80 of each tumbler.

The second cut-away portion 68 of each tumbler extends from step 81defining the extremity of the first cut-away portion arcuately above theperiphery so that in the datum position of the tumblers with respect tothe cylinder, the radius determining the extremity of the second radialedge 83 will engage the adjacent edge 200 of cylinder bridge element 51.

, Each of. the tumblers 64 are spaced apart from each other and theadjacent front end member and rear end member of the carrier 48, bymeans of spacers 65. Each of spacers 65 is in the general form of aBelleville type washer (see FIG. 7), and serves to provide theflexibility necessary to, ensure that each spacer imposes sufficientfriction to provide free movement of the tumblers and yet to permit eachtumbler to be rotated indepen: dently by the key. Each spacer 65comprises a keyhole 84 having a circular central portion 85 and asectoral portion 86 adapted to accomodate th bit of the key duringrotational movement of the key to engage the appropriate pick up stepson the tumblers 64. Each spacer is cut-away at a peripheral edge todefine a first inner cut-away portion 87 and a second outer cut-awayportion 88, the first inner cut-away portion is generally arcuate inform and defined at each end by a radius, the inner arcuate surface ofsaid first cut-away portion incorporates a notch 89, the ends of saidinner cut-away portion 87 embracing guide elements 43 of plug 32. Thesecond cut-away portion is a shallower arcuate portion communicatingwith the first and extends arcuately thereof so that the sum of thefirst and second cutaway portion corresponds with the extremity of thefirst and second cut-away portion of each tumbler. The extremity of thefirstcut-away portion 87 of each spacer is arranged so that the firstcut-away portion accomodates guide elements 43 of plug element 32, thenotch 89 being disposed to correspond with the spaced parallel guidefaces 47 of each of elements 43, the arrangement being suchthat inoperation the spacers rotate with the plug element 32 and the tumblers64 rotate relative to the spacers.

, Each spacer has one or more radially extending 1on gitudinal ribs 90and the spacers are manufactured in beryllium/copper or nickel silveralloys and provide a similar function to a Belleville washer.

Forwardly of the cylinder 48 there is disposed in bore I 13 of body 10 afront plate 91. The front plate 91 is of generally disc-shapedconfiguration and is adapted for rotation with the key and cylinder 48.The front plate 91 is manufactured from sintered carbide or otherhardened material and serves to prevent or restrain attack on thelocking mechanism by means of drilling. The front plate 91 is providedwith a central key-hole indicated generally at 92 of a configurationidentical to and corresponding with key opening 17 and cylinder frontend member 49. The arrangement is such that the front plate 91 iscontiguous with the front surface of the cylinder front end member 49.The front plate has a circular hole adjacent the key opening adapted toreceive the thicker shank portion of pin 62 so that in the assembledposition the reduced portion 63 of pin 62 projects forwardly of frontplate 91, the arrangement being such that the pin engages said frontplate 91 for rotation with detainer carrier 48.

The guide elements 43 of plug 32 encompass a generally rectangular sidebar 92 having a length corresponding to the space between the front faceof cylinder front end member 49 and of the rear face of cylinder rearend member 50, said side bar 92 being of longitudinal cross-section andadapted as a sliding fit relative to guide elements 43, and radially ofcylinder 30. The side bar 92 has planar rectangular surfaces 93 adjacentthe guide surfaces 47 and has a convex semi-circular outer surface 94.The inner surface 96 is radiused to correspond with the arcuate edge 80of first cut-away portion of each tumbler. The edge defining thecontiguity of one surface 93 and the radiused inner surface 95 ischamfered in each of the portion juxtaposed the cylinder front endmember 49 and the cylinder rear end member 50 for engagement with thecam surface 60 of the cut-away portion of the said members.

The arrangement is such that in the datum position of cylinder 30, theinner arcuate surface 80 of each of the tumblers 64 and thecorresponding inner arcuate surface 57 of each of the front end member49 and rear end members 50 of the cylinder cylinder is disposed adjacentthe radiused inner surface 96 and side bar 92, and maintains the sidebar 92 in a position such that it projects from the periphery of thecylinder assembly 30 into side bar recess 26.

The space between the front face of front plate 91 and the rear face ofinwardly directed flange 15 is occupied by a front spring plate 96 and arearspring plate 97, the front spring plate 96 being contiguous with therear surface of flange l anf body and the rear spring plate beingdisposed between the front spring plate 96 and front 'plate 91. Each ofthe spring plates 96 and 97 comprises a generally disc-shaped plateelement having a keyhole 99 corresponding to that in the front plate. Anarcuate slot 100 extends about the central portion of the keyhole andterminates at a point spaced on either side of said keyhole 99. Thewidth of the slot is sufficient to accomodate the reduced portion 63 ofpin 62, the arrangement being such that the pin can pass above the slotto permit the cylinder 48 to rotate above the axis of bore 13 withrespect to plate element 98. The periphery of plate element 98 isprovided with a projection 101 extending outwardly and in the planethereof and configured to fit into the side bar recess 26, thearrangement being such that the projection secured each of spring plates96 and 97 against rotation with respect to body 10.

The slot 100 accomodates a flexible compression spring 102. A first endof compression spring 102 remote from pin 63 is carried about an arcuateabutment 103 of circular cross-section. The second end of compressionspring 102 acts against pin 63 to bias pin 63 and the cylinder securedthereto to a datum position at the extremity of slot 100.

A key suitable for use in conjunction with the lock described above isshown in FIG. 8 of the accompanying drawings. This key 104 comprises ashank 105 projecting from a finger grip or bow 106. The portion of theshank 107 adjacent bow 106 is in the form of a collar and the majorportion of the shank extending from an extremity of the collar is ofreduced diameter and serves to define a pin 108. The annular facedefined between pin 108 and collar 107 acts to locate the key withrespect to the lock on insertion therein. The pin 108 carries agenerally planar' bit 109 extending radially outwardly of the pin 108,the thickness of bit 109 being substantially uniform. The outer edge 110is profiled with a plurality of steps each step corresponding to the keyengaging surface of a tumbler in cylinder 30. The front portion 111extends to the extremity of edge 1 10 for the purpose of engaging withfront plate 91 and the front end member 49 of detainer carrier 48.

It will be appreciated that the steps in contoured edge 1 10 of key 104are adapted to correspond with the first, second, third or fourth stepsof the pick-up steps 74 of each tumbler 64. The contour each step in thekey bit will relate to the angular spacing between notch 82 and thecorresponding pick-up step. The constant angular relationship betweenthe selected step and the notch is maintained so that when the key isturned the notches will be aligned.

In operation, the spring 102 biases pin 63 on the front end member 49 ofcylinder 48 to abut the adjacent extremity of slot 102, thereby defininga datum position for the assembly. At the same time, radial edge 200 ofbridge element 51 abuts radial edge 83 of each tumbler to maintain eachtumbler in its corresponding datum position with shoulder 79 abuttingadjacent side bar guide 43. In consequence, a peripheral arcuate edge 80of each tumbler 64 is juxtaposed at the radiused inner surface 96 ofside bar 92 to maintain the side bar 92 in the projected position sothat the convex outer surface 94 of side bar 92 is disposed in side barrecess 26. In this position the keyholes in each of the spring plates 96and 97, the front plate 91, the front'end member 49 of cylinder 48, eachof the tumbler 64 and the rear end member 50 of cylinder 48 are alignedand maintained in the aligned location by the spring bias applied to pin63 carried by cylinder front end member 49.

The key 104 described above and illustrated in FIG. 8 is inserted intothe key apertures 16 of the body member 10. Insertion of the key iscontinued until the annular rear face of collar 107 abuts the front faceof front spring plate 96. In this location the bit 109 of key 104 isdisposed and accomodated within the keyhole in each of front plate 91,cylinder front end member 49, each of cylinder 64 and theircorresponding spacers 65. The pin projection at the rear of the keyenters bore 36 for accomodation therein. v

The key 104 is, therefore, supported for rotation about the shank axisby the bore 36 and plug 32 and the spring plates 96 and 97. Rotation ofthe key in a clockwise direction with respect to FIG. 2 producescorresponding movement of the cylinder due to coaction between portion111 of the key bit 108 and the longitudinal walls of rectangular portion54 of key opening 52 in both cylinder front end member 49 and in frontplate 91. The initial rotation of the key produces rotation of thecylinder with respect to the tumblers to remove the radial extremity ofbridge piece 51 from its abutting relation with radial edge 83 of eachtumblersContinued rotation will bring the extreme portions of the keybit 109 into abutment with the first pickup step 74 of the tumblerscontiguous with said portion of the key. Thus, the picked-up" tumblerswill be caused to .rotate under the influence of the key while theportions of the bit of reduced radial extent from the axis of the keyshank will not abut a pick-up step and thus some of the tumblers will becaused to rotate about the axis of bore 13 with respect to theremainder. Further rotation of the key will produce contact betweenslightly reduced portions of the key bit and the second pick-up step ofthe appropriate detainers contiguous with said slightly reduced portion,thereby aligning the notches in the secondly picked up tumblers.Continued rotation of the key will produce a corresponding pick up ofthe third pick up step and the fourth pick up step, the arrangementbeing such that the notches82 in each tumblers will be aligned.Continued rotation will bring second radial abutment surface 58 intoabutting relationship with the adjacent side bar guide 43 whereby thenotched surface 59 in each of cylinder front end member 49 and cylinderrear end member 50 together with the notches 82 in each of the tumblers64- will be aligned contiguous to the radiused inner surface 95 of sidebar 92. Continued rotation of the key about its axis will producecontinued rotation of cylinder 48 and will serve to drive the plug 32about its axis by virtue of the abutment of the second radial abutmentsurface 58 of the cylinder against the corresponding surface of theadjacent side bar guide 43. The side bar 92 is thus urged arcuatelyabout the axis of bore 13 and the con vex outer surface 95 of side bar92 is caused to react against cam surface 29 of longitudinal side barrecess 26 to urge the talon inwardly of spaced talon guide 43 so thatthe radiused inner surface 95 enters the aligned notches 82of each ofthe detainers. Continued rotation of the key about its axis results inthe side bar 92 being urged into the notch until the extremity of theconvex outer surface 94 of side bar 92 is contiguous with or disposedwithin the peripheral circumference of cylinder 30. The rotationalmotion of the cylinder 48 serves to drive side bar guides 43 and henceplug 32 in rotary motion about the plug axis and thus connecting bar 40is caused to rotate to operate the lock to the unlocked position inwhich the pin 63 abuts an extremity of abutment member 103. It will beappreciated that since face plate 91 rotates with cylinder 48 and thespring plates 96 and 97 remain stationary, it is not possible towithdraw the key from the lock when the lock assembly is in the unlockedposition. Accordingly, in order to withdraw the key, it isnecessary toreturn the key to its datum position (anti-clockwise as viewed in FIG.2) or to release the key whereupon the first radial abutment surface 56of front end member 49 and rear end member 50 of detainer carrier 48abut the adjacent side bar guide 43 and drive the side bar guide andplug towards its datum location. As the spaced guide surfaces 47approach recess 26 the cam surfaces 60 on each of said front end member49 and said rear end member 50 act on the chamfered portion of the sidebar 92 to urge the the influence of spring 102 or the return of the keyto its datum position causes the side bar to be urged outwardly of theplug and into side bar recess 26 until the adjacent rectangular surface96 of side bar 92 abuts radial surface 27 of side bar recess 26 therebypreventing further rotation of the plug assembly and locating the plugassembly 32 in its datum position. At the same time the spring 102continues to bias pin 63 towards its datum position at the extremity ofslot 100. The notches 82 in the tumbler 64 are now free to be dispersed.Lost motion then occurs between the respective tumblers 64 until theradial edge 83 is picked-up" by edge 200 of bridge element 51. Rotationcontinues until the cylinder and each tumbler reaches its datumposition, in which the shoulder 79 oneach detainer abuts the radialsurface 46 of side bar guide 43.v

It will be appreciated that dummy notches of some 10 or 15 thousandthsof an inch depression in the periphery of the arcuate edge 80 of each.tumber can provide additional hazard to picking of the lock- It isnecessary to pick accurately 10 members and at the same time to maintaina bias on the cylinder to urge side bar 92 to the commencement of camsurface 29. The presence of dummy notches will result in one or moredummy notches being engaged, in which case the only means of releasingthe dummy notch is to release the cylinder I to allow the cylinder 48 toreturn to its datum under the spring bias andto start again.

An alternative embodiment of the present invention is illustrated inFIG. 9. In this embodiment the talon guides 43 are secured to. and formpart of the cylinder 48 so that the side bar 92 is arrangedfor rotationwith the pick up steps 74 of each of tumblers 64. The side bar isprovided with a pair of axially extending projections 113 at each endthereof and the front face of plug element 32 is provided with atrack toaccomodate the rearwardly projecting element 113 while the spring 96 and97 are provided with a cut-away portion 114 to define a track for theforward projection 113 of side bar side bar outwardly of the cylinderassembly. Continued rotation of the plug 32 and the side bar guides 43under axisof bore 13 to produce corresponding movement of 7 side barguides 43 and side bar 92. Continued rotational movement of the keyproduces corresponding arcuate movement of the side bar within the trackdefined by recess 26. At the same time pickup of the step 74 of thetumblers 64 occurs as before and the notches 82 are aligned as the sidebar approaches cam surface 29. Continued rotation of the key producesreaction between side bar 92 and cam surface 29 to urge the side barinwardly of cylinder 30 to cause projection 1 13 to enter the trackdefined by the cut-away portion 114 of each of the spring plates andthecorresponding track provided in the front face of plug 32 and bypermitting continued rotation of the key until pin 63 engages abutmentmember 103.

On returning the key to its datum position or allowing the key toreturnto its datum position under influence of spring loading ofcompression spring 102, the side bar is caused to rotate with thecylinder 48 until the extremity of the side bar 92 is juxtaposed camsurface 29. Thereupon the projection 113 engage cam surfaces in each ofthe spring plates and in the corresponding surface in plug 32 to urgethe side bar outwardly of cylinder 30.

In the embodiment, illustrated in FIG. 10, the spring plate assemblyillustrated in FIG. 3 may be substituted by a spring plate assembly asillustrated in FIG. 9. In this case a toggle spring 115 may be employed,having an end 1 16 disposed about pin 63. A second end of the togglespring may contain a hemi-spherical element 117 adapted to abut againstand swivel about arcuate portion 118 of the spring recess.

In operation, movement of the pin arcuately within the recess 100results in compression of the spring against hemi-spherical element 118until the centre point of pin 63 passes over centre of arcuate portion118 with the result that the spring acts to urge pin 63 to the upperextremity of the recess 100, thereby providing an over centre"arrangement for the lock. In this case a return action has to beprovided from the key against the spring loading of pin 63 into thesecond extremity of recess 100 until the pin again passes over thecentre, whereupon the spring urges pin 63 to a datum position and acorresponding urge applied to the cylinder 48 and tumblers carriedthereby.

In a further embodiment of the present invention, the cylinder may bearranged so that there is lost motion between the key and the cylinderuntil the notches 82 in each of the tumbler are aligned.

This embodiment is illustrated in FIGS. 11 to 15 of 'the accompanyingdrawings. In order to achieve this variant of the lock assembly of thepresent invention, the cylinder 48 comprises the carrier front endmember 49 and the cylinder rear end member 50, the said members beingdisposed in spaced parallel relationship. The members 49 and 50 aremaintained in a spaced parallel relationship by means of spaced side barguide members 43. Each of these members have a configurationcorresponding to that described with reference to FIG. 1. The front andrear end members 49 and 50 respectively, comprising a disc of materialadapted for a rotational fit in bore 13 of body member 10. The front endmember of 49 of cylinder 48 has a keyhole 52 comprised by a circularaperture part 53 adapted to accomodate the shank or pin of the keyitself and a sector portion 1 19 which attends an angle of substantially90 at or towards the centre of the disc constituting front end member49, thearrangement being such that the key is free to turn through anangle of substantially 90 without abutting an extremity of key opening52, thereby providing clearance for key rotation to align the notches 82in each of tumbler 64 prior to commencing turning of the cylinder 48.The front face of front end member 49 has a forwardly projecting spigot120 of circular cross-section, the centre of which lies in a diameterwhich substantially bisects the angles subtended by the radial extremityof centre portion 119 of the key opening 52. Spigot 120 is disposed sothat the cylindrical surface 121 has a common tangent with the peripheryof the disc constituting front end member 49.

The tumblers and spacers are disposed between front end member 49 andrear end member 50 in a manner described with reference to FIG. 1, theconfiguration of the cut-away portion of each tumbler member being suchas suitably to accomodate the side bar guides 43.

The front plate 91 has a keyhole corresponding to that of the frontplate of the assembly described with respect to FIG. 1 and adjacent thekeyhole a spring drive pin 122 is carried to extend forwardly of thefront surface of front plate 91. The portion of the periphery remotefrom the rectangular portion of the keyhole of front plate 91 iscut-away to define a substantially radial drive face 123', an arcuatesurface 124 spaced inwardly of the periphery of the disc defining frontplate 91 and a second radial spigot abutment surface 125. The pin 122 isadapted to enter into slot of spring plates 96 and 97 to act in themanner described above.

In operation, the key is inserted into the keyhole with .the bitentering the appropriate portion of the hole provided therefor in eachof the tumblers. The key is thus inserted at the datum position in whichthe second radial pin abutment surface 125 is in abutting relationshipwith the spigot 120 of cylinder front end member 49. The spring 102acting on pin 122 to bias said front plate 91 to the datum position.Rotation of the key causes the bit thereof to engage the side of thekeyhole in front plate 91 to drive front plate 91 about its axis againstthe spring bias acting on pin 122. The said portion of keyhole 52 in thecylinder front end member 49 allows the key to turn without impartingmotion thereto. As progressive rotation of the key produces alignment ofthe notches 82 in tumblers 64'carried by the cylinder 48 in the mannerdescribed above, when the notches are aligned the drive face 123 offront plate 91 engages the diametrically opposite extremity of spigot120 on cylinder front end member 49. Continued rotation of the keyimparts drive to the cylinder 48 through spigot 120. In this positionthe notches 82 are aligned contiguous the radiused inner surface of sidebar 92 and further rotation of the key causes rotation of side barguides 43 to urge the extremity of the side bar against cam surface 29to permit rotation of the cylinder with respect to body 10 to theunlocked position. On retumor release of the key the spring 102 urgespin 122 towards its datum position until the side bar 92 is juxtaposedin the side bar recess 26, whereupon the side bar returns to recess 26and the cylinder 48 is maintained in the stationary position and the pin122 on front plate 91 is' urged to its datum position, whereby thenotches 82 in each of the tumblers 64 are dispersed and the key can thenbe withdrawn.

In a modification of the embodiment described, the spring assembly maybe modified in a manner shown in FIG. 15. The spring plate is providedwith a spring support pin 126 carried by the front spring plate 91 whichpin 126 carries a leaf spring 127 formed of spring steel. A first end128 of spring 127 is biased against the cylindrical surface of bore 13of the body 10. The spring then passes about pin 126 in a coil129 andthe second end 130 is partially cranked at 131 to provide a convexsurface which acts against pin 122 to bias it to its datum position. Thespring leaf 127 extending across the front surface of front plate 91over a path shorter than a circumferential path.

In operation, rotation of the key drives front plate 91 in the mannerdescribed above. The pin 122 moves against the bias of spring 127 toflex the same against stationary pin 126. Continued rotation of the keyresults in continued rotation of front plate 91 until pin 122 has urgedleaf spring 127 to flex outwardly of a circumferential path contained bythe radial extremity of pin 122. At this point the pin 122 rides underthe cranked portion 131 of leaf spring 127 and the spring bears againstthe pin 122 to provide resistance to turning so that the lock may beturned to a dead lock position. Upon returning to the datum position, asthe pin 122 passes about the cranked portion 131 of leaf spring 127 thesaid portion engages the pin and biases the pin towards the datumposition in the manner described above.

In a further embodiment of the present invention as set out in FIGS. 16to 19 of the accompanying drawings, each of the individual tumblers isspring loaded to its datum position. This renders the lockssubstantially pick proof, and in order to pick the lock it would benecessary to employ a lock picking device having N+1 elements where N isthe number of tumblers.

In this embodiment (see FIG. 17) the talon recess 26 is accomodatedwithin an inwardly raised portion 132 defined by a pair of radialshoulders 133 and 133. A plug indicated generally at 32 comprises aplurality of cylinders 134 each of which interlocks one with the other,the number of cylinders 134 being equal to the number of tumblers 64employed in the assembly. The plug also includes a rear spring plate 135and a front spring plate 136, a front plate 191 being disposed betweenfront spring plate 136 and the first cylinder 134.

Each cylinder comprises 'a disc 137 having a forwardly extendinggenerally annular projection 138 defining a substantially cylindricaldepression 139 adapted to carry a tumbler 64. Each detainer carrier isprovided with a substantially radial slot 140 adapted to accomodate theside bar, the opposed faces of slot 141 of slot 140 definezthe guidesurfaces for the side bar itself. Juxtaposed on each side of slot 140there is provided on the front face of each tumbler a forwardlyextending stud 142 which is adapted to engage with a correspondingrecess 143 in the rear face of the preceding cylinder element to lockone with respect to the other. An arcuate flange 144 is located on theperiphery of disc 137 and extends forwardly of the front forwardextremity of the annular projection 138 to mate with a correspondingrecess 145 in the rearward surface of the preceding tumbler, thearrangement being such that by interlocking of the projecting parts withthe corresponding recesses on the preceding element a cylinder can bebuilt up.

The peripheral edge of the tumblers is cut away at 146 to provide afirst shoulder 147 and a second shoulder 148 each of which is adapted toabut shoulders 133 'and 133' respectively at different attitudes of thecylinder.

The keyhole 149 of tumbler 134 is sectored so that the key disposedtherein is capable of an arcuate movement through an angle ofsubstantially 90 without corresponding movement of the carrier.

Each tumbler 134 carries a tumbler 64 configured and adapted to beaccomodated therein. A first tumbler projection 151 engages a tumblerspring 150 which is biased against the corresponding abutment as part ofthe thickened portion of the annular projection 138 juxtaposed the sidebar accomodating slot 140, the arrangement being such as to bias thetumbler to its datum position whereby a second abutment surface 152engages the corresponding surface of the other thickened portion withthe forward annular projection 138 of the adjacent to side bar slot 140.

The remainder of the assembly is similar in construction with theembodiments described above. The spring plate illustrated in FIG. 18 isprovided with a track to accomodate a side bar projection in the mannerdescribed above, and the spring assembly of the spring plate is alsodescribed in detail above.

In operation, insertion of the key with the lock elements in the datumposition permits the key to engage the spring plate the front plate andthe tumblers themselves. Rotation of the key about its axis causespick-up of the various pick-up steps on the tumblers until the notches82 are aligned for subsequent accomodation of the side bar. At the sametime, the tumblers are rotated about their axis against their springloading until shoulder 133' abuts corresponding third shoulder 153 onthe. At this stage the notches 82 are aligned juxtaposed side bar 92 andreaction of the extremity of the side bar 92 against the cam surface ofrecess 26 urges the side bar inwardly and permits rotation of thecomposite cylinder. Rotation of the tumblers together with the turnblers contained therein and the side bar now accomodated within thealigned notch 82 continues until shoulder 148 abuts shoulder 133' on thebody.

It will be appreciated that the compression spring 102 should be greaterin strength than the combined compressed strength of each of the tumblersprings so that the drive will not be transmitted to the cylinder untilthe tumbler have been partially rotated against their spring bias toalign the notches 82 to accomodate the inner portion of the side bar 92.

What I claim is:

1. A lock comprising a housing having a recessed area on the inner wallthereof, a lock cylinder in said housing having spaced front and rearend walls, a plurality of key-operated tumblers'in said cylinder, pinmeans carried by the front wall of said lock cylinder capable ofoscillating the lock cylinder from a locking position to an unlockingposition, means abutting the rear wall of said lock cylinder associatedwith an axially disposed connecting bar and means capable of actuatingthe tumblers in succession to urge a side bar into said recess to permitthe connecting bar to move to an unlocking position.

2. A lock as claimed in claim 1, wherein resilient means cooperate withsaid pin means.

3. A lock as claimed in claim 2, wherein the spring means is interposedbetween plural oscillatable plate means. r

4. A lock as claimed in claim 3, wherein the front wall of the lockcylinder and said oscillatable plate means are maintained in spacedrelation by front plate means.

5. A lock as claimed in claim 2, wherein the resilient means iscontrolled by a V-shaped slot and serves to confine the pin means in anarcuate path of travel from a locking position of the cylinder to anunlocking position thereof and vice-versa.

' 6. A lock as claimed in claim 4, wherein the front plate means isarranged to be rotated by a key against the spring bias of a second pinmeans.

7. A lock as claimed in claim 2, wherein the resilient means comprisesaleaf spring.

8. A lock as claimed in claim 1, wherein the side bar cooperates with aradial slot in said tumblers.

9. A lock as claimed in claim 8, wherein the radial slot is straddled byoffstanding studs.

10. A lock as claimed in claim 1, wherein the tumblers are spring-loadedinto their locking position.

11. A lock as claimed in claim 1,. wherein spacer elements areinterposed between the inner walls and each of said tumblers.

1. A lock comprising a housing having a recessed area on the inner wallthereof, a lock cylinder in said housing having spaced front and rearend walls, a plurality of key-operated tumblers in said cylinder, pinmeans carried by the front wall of said lock cylinder capable ofoscillating the lock cylinder from a locking position to an unlockingposition, means abutting the rear wall of said lock cylinder associatedwith an axially disposed connecting bar and means capable of actuatingthe tumblers in succession to urge a side bar into said recess to permitthe connecting bar to move to an unlocking position.
 2. A lock asclaimed in claim 1, wherein resilient means cooperate with said pinmeans.
 3. A lock as claimed in claim 2, wherein the spring means isinterposed between plural oscillatable plate means.
 4. A lock as claimedin claim 3, wherein the front wall of the lock cylinder and saidoscillatable plate means are maintained in spaced relation by frontplate means.
 5. A lock as claimed in claim 2, wherein the resilientmeans is controlled by a V-shaped slot and serves to confine the pinmeans in an arcuate path of travel from a locking position of thecylinder to an unlocking position thereof and vice-versa.
 6. A lock asclaimed in claim 4, wherein the front plate means is arranged to berotated by a key against the spring bias of a second pin means.
 7. Alock as claimed in claim 2, wherein the resilient means comprises a leafspring.
 8. A lock as claimed in claim 1, wherein the side bar cooperateswith a radial slot in said tumblers.
 9. A lock as claimed in claim 8,wherein the radial slot is straddled by offstanding studs.
 10. A lock asclaimed in claim 1, wherein the tumblers are spring-loaded into theirlocking position.
 11. A lock as claimed in claim 1, wherein spacerelements are interposed between the inner walls and each of saidtumblers.